With the recent advancement and development of portable information devices such as cellular phones, there has been a demand for alkaline dry batteries capable of discharging under a heavy load.
In response to this, for the purpose of improving heavy load discharge characteristics of alkaline dry batteries, the conventional alkaline dry batteries have employed, as a positive electrode additive, an anatase titanium oxide (e.g., Japanese Laid-Open Patent Publication No. Hei 8-510355), a titanium-containing composite oxide (e.g., Japanese Laid-Open Patent Publication No. Hei 9-139201) and a barium compound such as barium sulfate (e.g., International Publication No. WO 00/30198).
However, although the addition of titanium oxide, a titanium-containing composite oxide or a barium compound to a positive electrode improves the heavy load discharge characteristic to some extent, it does not yield a sufficient active material utilization rate. Moreover, in order for the aforesaid conventional additives to provide sufficient effects, they need to be employed in a large amount. Accordingly, a filled amount of manganese dioxide which serves as an active material in the positive electrode decreases, thereby decreasing the electrical capacity of the battery and reducing the light load discharge characteristic thereof. This also causes a great inconvenience for the use of equipment such as timepieces which require discharging under a light load, since there still exists a considerable demand for alkaline dry batteries.
It is an object of the present invention to provide an alkaline dry battery which has excellent heavy load and intermediate load discharge characteristics, and in which reduction in light load discharge characteristic is suppressed.